Upgrading a network as large as Comcast's to support IPv6 is "non trivial," Brzozowski says.
Comcast has been working on its IPv6 deployment for seven years, starting with the ability to manage its own network devices using IPv6, then migrating the company's internal network to IPv6, and now deploying IPv6 to all of its residential customers in a seamless, non-disruptive manner.
Comcast says its entire network will support IPv6 by the end of 2012.
"What we're really talking about is enabling high-speed data," Brzozowski says. "We've made sure that everything we designed, developed and deployed could support IPv6 at scale. Everything had to be the same with IPv6 as with IPv4. We couldn't put IPv6 in our customers' hands that was below par."
Comcast's IPv6 service for home networking users is the latest in a series of IPv6-related announcements that the company has made in the last five months.
In a somewhat controversial move, Comcast is giving each of its home networking users what's called a /64 block of IPv6 addresses, which represents more than 18 quintillion IPv6 addresses or 18,446,744,073,709,551,616 to be exact. This is a massive amount of IP addresses for techies to ponder given how long they've functioned in the address-constrained mode of IPv4.
Brzozowski said Comcast has to give a /64 set of IPv6 addresses because that's the only size of IP address blocks that CPE supports today. He said Comcast will re-number its initial home gateway customers with smaller blocks of IPv6 addresses once home gateway makers have compliant, interoperable products that support this feature.
"We have no intention of staying fixed on /64s," Brzozowski said. "Our goal is to get something out sooner rather than later, then we'll go back and incrementally introduce support for shorter prefixes. Maybe later this year we will be prepared to have Version 2 of our home networking service with shorter prefixes."
Until recently, home gateways have been a major stumbling block for ISPs like Comcast that are trying to deploy IPv6 because the devices lacked support for the new standard. Home gateways are mini-routers with firewall capabilities that consumers use to create networks in their homes, connecting PCs, tablets, TVs and gaming systems to the Internet.